The South American Monsoon System Recent Evolution and

The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 13 February 2012 For more information, visit: http: //www. cpc. ncep. noaa. gov/products/Global_Monsoons/American_Monsoons

Outline • Highlights • Recent Evolution and Current Conditions • NCEP/GFS Model Forecasts • Climatology

Highlights • During the last 7 days, above-average rainfall was mainly observed over northwestern South America and portions of northern Argentina, and Uruguay. Below-average rainfall was observed over much of Brazil (except the northwest), eastern Peru, and portions of northeastern Argentina, southern Bolivia, and southern Paraguay. • For 13 -19 Feb 2012, above-average rainfall is predicted mainly over northeastern and southwestern Brazil, southern Peru, and northern Bolivia. Below-average rainfall is predicted over northwestern and southern Brazil, Colombia, central Peru, southern Bolivia, and northeastern Argentina. • For 20 -26 Feb 2012, above-average rainfall is predicted over northernnorthwestern Brazil, French Guiana, southern Colombia, eastern Ecuador, northern and southern Peru, northern Paraguay, and northern Argentina. Below-average rainfall is predicted mainly over southern Brazil and eastern Peru.

Rainfall Total & Anomaly Patterns: Last 7 Days Total Anomaly During the last 7 days, above-average rainfall was mainly observed over northwestern South America and portions of northern Argentina, and Uruguay. Below-average rainfall was observed over much of Brazil (except the northwest), eastern Peru, and portions of northeastern Argentina, southern Bolivia, and southern Paraguay.

Rainfall Totals & Anomaly Patterns: Last 30 Days Total Anomaly During the last 30 days, above-average rainfall was mainly observed over northwestern South America, northern Paraguay, and portions of central Brazil and northern Bolivia. Below-average rainfall was seen over most of Brazil (especially the southeast), eastern Peru, southeastern Bolivia, southern Paraguay, and northern Argentina.

Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau BP • 90 -day rainfall totals are below average over the southern Amazon basin. They are also slightly below average over the Brazilian Plateau, the core monsoon region. • 90 -day totals are significantly below average in southern Brazil.

Tropical Pacific and Atlantic SST Anomalies Unavailable this time A weekly Power. Point summarizing the ENSO Cycle: Recent Evolution, Current Status and Predictions is available at: http: //www. cpc. noaa. gov/products/precip/CWlink/MJO/enso. shtml

Atmospheric Circulation Recent 7 days C A During the period of 3 -9 February 2012, an anomalous cyclonic pattern (C) and an anomalous anti-cyclonic pattern (A) were observed over eastern Brazil and northern Argentina, respectively.

925 -h. Pa Wind &Temperature Recent 30 Days Recent 7 Days • During the 7 -day period of 4 -10 February 2012, temperatures were well above normal in southern Brazil. Low-level (~600 m) wind and temperature anomalies based on the NCEP Climate Data Assimilation Systems (CDAS) analysis. The patterns of anomalous temperature and wind at 925 -h. Pa are usually similar to surface observations. Note: Areas with surface pressure below 925 -h. Pa are masked out.

NCEP/GFS Model Forecasts Bias-Corrected Precipitation Forecasts from 13 February 2012 – Days 1 -7 Total Note: Bias correction based on last 30 -day forecast error. Anomaly

NCEP/GFS Model Forecasts Bias-Corrected Precipitation Forecasts from 13 February 2012 – Days 8 -14 Total Note: Bias correction based on last 30 -day forecast error. Anomaly

NCEP/GFS MODEL FORECASTS • For Days 1 -7 (13 -19 Feb 2012), above-average rainfall is predicted mainly over northeastern and southwestern Brazil, southern Peru, and northern Bolivia. Below-average rainfall is predicted over northwestern and southern Brazil, Colombia, central Peru, southern Bolivia, and northeastern Argentina. • For Days 8 -14 (20 -26 Feb 2012), above-average rainfall is predicted over northern-northwestern Brazil, French Guiana, southern Colombia, eastern Ecuador, northern and southern Peru, northern Paraguay, and northern Argentina. Below-average rainfall is predicted mainly over southern Brazil and eastern Peru.

Forecast Verification Forecast from 29 Jan 2012 Valid 5 -11 Feb 2012 Forecast from 6 Feb 2012 Valid 6 -12 Feb 2012 Observed 5 -11 Feb 2012

Climatology Rainy Season Dates ONSET DEMISE

Precipitation Climatology

Precipitation Climatology Animation